Electric-impulse counter



May 16, l1950 w. E. MAXWELL. 2,507,798

ELECTRIC IMPuLsE COUNTER /M/fA/ro/f WEYMAN E. MAxwaLL Arron/vir Milly 16, 1950 w, E, MAXWELL 2,507,798

ELECTRIC IMPULSE COUNTER Filed Ma'y 15, L945 2 sheets-sheet 2 L42 Fi G. a.

rro/twfrs Patented May 16, 1950 UNITED STATES PATENT OFFICE to rihe Standard Electric Time Company,

Springfield, Mass., a corporation of Connecticut Application May 15, 1945, Serial No. 593,947

4 Claims.

The present invention relates to impulse-counters and relates more particularly to impulsecounters which act to count or indicate electricimpulses such, for instance, as electric-impulses emanating from pickups located adjacent a machine gun to permit the rate of nre thereof to be ascertained, etc., etc.

One of the main objects of the present invention is to provide a superior electric-impulse counter which will provide trouble-free service over long periods of use.

Another` object of the present invention is to provide a superior` electric-impulse counter which will accurately count or indicate electricimpulses which follow each other at relativelyshort intervals, such for instance, as electric-impulses having frequencies of the order of 5000 per minute and up.

With the above and other objects in view, as will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art.

In the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposes:

Fig. 1 is a schematic View of one form of electric-impulse counter embodying the present invention;

Fig. 2 is an end View of the mechanical portions of the apparatus illustrated in the upper portion of Fig. l; and

Fig. 3 is a schematic representation ci another form of electric pickup-means suitable for energizing the mechanical portions of the apparatus illustrated in the upper portion of Fig. l and in Fig". 2.

The apparatus chosen for illustration in Figs. 1 and 2 for purposes of making clear one form of the present invention, includes a controlmember or cam l which may be rotated by any suitable means which will serve to synchronize the said control-member or cam with the operations Which it is desired to count. By way of eX- ample, it may be assumed that the control-cam l0 is rotated by internal combustion engine whose R. P. M. it is desired to ascertain. In this connection, however, it may here be pointed out that the control-member or cam I0 or its equivalent, may be operated by a wide variety of contrivances, such for instance as a conveyor belt, a sheet-stacker, etc., etc.

The control-cam l0 is adapted to lift the adjacent end of a switch-arm il, which is pivoted at a point remote from the control-cam l0, upon a pivot-pin l2 and is normally held in engagement with the periphery of the said control-cam by means of a spring I3. At its free end, the switch-arm i l carries a contact I4 which is adapted to engage with and disengage from a complemental contact l5, which latter is normally stationary.

The pivotal switch-arm H above referred to, is connected by means of a wire I6 to one terminal of a battery il or other suitable source of direct current supply. The opposite terminal of the battery il is connected by means of a wire i8 to one terminal of the primary-winding i9 of a transformer generally designated by the reference character 20. The opposite terminal of the primary-winding l0 is connected by means of a wire 2l to the stationary contact I5 which complements the movable contact I4 before referred to.

The transformer Ztl above referred to, also includes a secondary-winding 22 having one of its terminals connected by means of a wire 23 to a wire 26 which latter serves to interconnect the two adjacent terminals of two energizing-coils respectively designated by the reference characters 25 and 2S. The said energizing-coils 25 and 23 respectively encircle and serve to energize U-shaped pole-pieces 2l and 28. The said polepieces 2l and 28 are formed of magnetic material such, for instance, as soft iron, silicon steel or the like having low hysteresis characteristics. The pole-piece 2l is formed with two polesalients respectively designated by the reference characters 29 and S0, while the pole-piece 23 is likewise formed with two pole-salients 3| and 32.

The terminal of the energizing-coil 25 opposite the wire 2E, is connected by means of a Wire 33 to an intermediate tap 3d of the secondary-winding 22 before referred to. The terminal of the energizing-coil 26 opposite the interconnecting'- wire 24, is connected by means of a wire 35 to the right terminal of the secondary-Winding 22. nterposed in the wire 35 is a condenser 36 which is designed and adapted to cause the current in the energizing-coil 2S to lead the current in the energizing-coil 25 by substantially 90 electrical degrees, all for purposes as will more fully here inafter appear.

Returning now to the pole-piece 2l, it will be noted by reference to Fig. l that the pole-salients 29 and 30 thereof, are respectively located adjacent the peripheries of disk-like rotor-elements 31 and 38. Similarly, the pole-salients 3| and 32 of the pole-piece 28 are respectively located adjacent the peripheries of similar disk-like ro- 3s tor-elements 3e and lit. rThe rotor-elements 31 to El inclusive just referred to, are preferably formed of soft iron or equivalent non-permanent magnet material and are each formed with an annular series of pole-saliente 4I.

The rotor-elements Si" and 38 are relatively closely adjacent and are located at one end of a tubular permanent magnet 42 which is preferably formed of Alnico or other suitable permanent magnet material. The end of the permanent magnet 2 opposite the rotor-elements and Se, is in magnetic communication with the rotorelements and d. The result of the arrangement just described is that the said permanent magnet coincidentally imparts one fixed polarity to the pcle-salients di of the rotor-elements and SS while impressing an opposite permanent polarity to the pole-saliente i of the rotor-elements 3a and 4t.

It will be noted by reference to Fig. l, that the respective pole-salients lli of the rotor-elements 3'! and 38, are circumferentially displaced with respect to each other a distance equivalent to one full tooth. Similarly, the respective pole-saliente of the rotor-elements 39 and Sil are displaced with respect to each other a circumferential distance equal to one full tooth. It will further be noticed that the relative circumferential displacement between the pole-saliente .il of the rotor-element 33 and those of the rotor element 39 is equal to a distance of one-half tooth, all for purposes of insuring the stepbystep rotation of the rotor comprising the parts 3l to f inclusive, as the pole-pieces 2l and 28 are energized in sequence in a manner as will hereinafter appear.

The rotor-unit comprising the element to 132 inclusive, is mounted for rotation upon a rotorshaft 43 adapted to turn in any suitable bearings (not shown) and carries at its forward end a drive-pinion d4. The said drive-pinion meshes into and drives a gear-wheel 45 which is rigidly mounted upon the inner end of a bearingsleeve d5. The said bearing-sleeve rigidly carries at its forward end a friction coupling-disk il for purposes as will presently appear. The unit comprising the gear-wheel d5, bearing-sleeve and coupling-disk is mounted for rotation upon an arbor 132i which carries adjacent its inner end, a stop-collar 1353 against the forward face of which bears the inner face of the gear-wheel d5 before referred to.

Mounted upon the forward portion of the arbor 48 in front oi the coupling-disk d'1 and with freedom for both axial and turning movement on the said arbor, is a unit which comprises a stopwheel 5d having a serrated peripherv its integral hub 5l and a pointer 52 rigidly carried at the outer end of the said hub. Spaced forwardly of the pointer 5E and rigidly secured 'to the arbor t is a collar 53, against the inner face of which presses the forward end of a helical spring 555. The rear portion of the spring 54 presses against the forward face of the hub 5i and serves to frictionally engage the rear face of the stopwheel 5t with the forward face of the couplingdisk 4l' so as to provide the desired coefficient of friction therebetween.

rEhe friction-coupling just above referred to will under certain conditions, cause the coupling-disk di' to drive the unit comprising the stop-vvheel 5E?, hub 5i and pointer 52.

For the purpose of releasably restraining the unit comprising the parts 55, 5i and 52 against rotation, a stop-lever 55 is employed. The said stop-lever is formed of magnetic material and is Ll (l poleesalients 4i of the rotor-element d mounted intermediate its respective opposite ends upon a pivot-pin 56 and carries at its forward end a stop-finger 5l which is adapted to engage with the periphery of the stop-wheel 5@ to hold the latter against rotation. The stop-lever 55 is yieldingly urged to turn in the direction required to engage its stop-finger 51 with the periphery of the stop-wheel 5t, by means of a helical spring 55.

For the purpose of turning the stop-lever 55 against the tension of its spring 58 to withdraw the stop-finger 57 out of engagement with the serrations on the periphery of the stop-wheel 58, an electromagnet 59 is employed. rhe said electromagnet is connected by means oi two wires GG and 5l to the wires IG and i8 respectively, which latter are connected as before described, to the opposite terminals of the lbattery i l or other suitable source of direct current. interposed in the wire t! is a switch 62 by means of which the energization of the electromagnet 59 may be controlled.

Operation of the apparatus of Figs. 1 and 2 For purposes of description, let it be assumed that the control-cam lil is being rotated so as to cause (in conjunction with the spring i3) the movable Contact I4 to repeatedly engage with and then disengage from the stationary contact i5.

The engagement of the contact I4 with the contact I5 will close the circuit through the primary-winding i9 of the transformer Z and thereby induce a voltage in the secondary-winding L2. Due to the connections shown, the resultant vcltages in the secondary-winding 22 will be impressed upon the energizing-coils 25 and 2G with a relatively-high voltage being applied to the energizing-coil 26 and a relatively-lower voltage being applied to the energizing-coil 25. Due to the fact that the condenser 36 or its equivalent is interposed in the circuit of the energizing-coil LS, the current passing through the said energizing coil will lead that passing through the complemental energizing-coil 25 by substantially 90 electrical degrees. Thus, in a manner well known in the art, the condenser 36 acts to shift the phase of the current in the circuit ol' the coil with respect to that in the coil 25.

From the foregoing it will be seen that the energizing-coil 26 will be the rst to respond to the transient induced in the seconda1y\;vinding 22 as a result of the closing of the contacts I4 and l5. Hence the pole-salient 32 of the polepiece will attract the adjacent one oil the (due to opposite polarities at this instant) while at the same time that the complemental Ipole-salient IH is acting to repulse its adjacent pole-salient 4i of the rotor-element 39, with the net result that the rotor-unit will be advanced distance equivalent to one-half tooth in the direction indicated by the arrow in Fig. 2.

Substantially electrical degrees later the pole-piece 2l' will act through its pole-salients 29 and 3B to respectively act on the rotor-elements 3l and 5S to turn the rotor-unit a further distance equivalent to one-half tooth.

From the foregoing it will be seen that one maire of the contacts E4 and l5 will cause a rotation of the rotor-unit equivalent to one full tooth for what is equivalent to one-hall' cycle of energization.

Now as the control-cam IG rotates and permits the contact if; to separate from the contact I5, the circuit Wil be broken and a transient voltage of reverse polarity will be produced by the magnetic energy stored in the core of the transformer 20. This transient voltage will again cause a leading current to liow through the energizingcoil 26 to again advance the rotor-unit the equivalent of one-half tooth to be followed substantially 90 electrical degrees later by the peak energization of the energizing-coil to thereby further turn the rotor-unit a distance equivalent to another half tooth.

From the foregoing it will be seen that for each cycle of make and break of the contacts I4 and i5, the rotor-unit, considered as a whole, Will be rotated a distance equivalent to two teeth.

Under the conditions here being described, the turning of the rotor-unit, as a whole, will act through the rotor-shaft 43, drive-pinion dll, gearwheel t5 and bearing-sleeve 46 to turn the coupling-disk dl. Due to the fact that at this time the stop-finger 51 is in engagement with the serrated periphery of the stop-wheel 5G, the latter will remain stationary while the coupling-disk 4l will slip due to its frictional engagement with the said stop-wheel 5d.

For purposes of description let it further be assumed that it is desired to determine the R. P. M. of a prime mover such, for instance, as an airplane engine, in which case the controlcam It would be suitably connected to such engine to cause it to revolve in consonance with the engine. Now with the aid of a stop watch or its equivalent, the counting cycle may be started by closing the switch 62. Upon closing the switch 62 the electromagnet 59 will be energized to thereby attract the stop-lever 55 and turn the same in a counterclockwise direction about the pivot-pin 56, to thus withdraw the stopfinger 5l from engagement with the periphery of the stop-wheel 5d. When thus released, the stopwheel 5t will be substantially instantaneously started into motion by the friction of the coupling-disk Lil and will, of course, coincidentally turn the pointer 52.

As soon as the counting cycle is concluded, the

opening of the switch t2 will deenergize the elecl tromagnet 59 thereby permitting the spring 5B to act through the stop-lever 55 to re-engage the stop-finger i-'i with the serrated periphery of the stop-wheel t@ to substantially instantaneously check the further movement thereof despite the friction drive of the coupling-disk 4l. In some installations the switch 52 or its equivalent may be automatically operated s0 as to close and open at predetermined intervals.

In instances where it is desired to employ the electric-impulse counter, above described, for purposes of counting sheets as the same are stacked in a pile, the control-cam it may be suitably connected to the stacker so that the said controlcam can turn one complete revolution for the stacking oi each single sheet. During the counting period the switch 62 would remain closed so that the pointer 52 may be turned to record each sheet so stacked.

By employing a split-phase self-starting motorstructure of the permanently-magnetized rotor type capable of having the movement oi its rotor take place in a step-by-step manner, in conjunction with a transformer or equivalent inductance7 both the eects of the make and the break of the circuit are utilized to operate such a motor. Thus, accurate counting of electric impulses may be achieved even when such impulses follow each other at a rate greatly in eX- cess of five thousand impulses per minute.

The apparatus of Fig. 3

The apparatus illustrated in Fig. 3 is designed and adapted to eiect the energization of a selfstarting synchronous electric motor like that shown in the upper portion of Fig. 1 in lieu of the portion of the apparatus shown in the lower portion of the said figure.

The apparatus illustrated in Fig. 3 includes the transformer F.l, the switch-arm I l and associated parts, as well as the switch 62 for controlling the energization of an electromagnet like 59. In addition, the apparatus includes a direct current power-pack 53, a power-amplifying tube 64, `which latter in the instance shown is a tetrode-tube comprising a plate 65, a screen-grid 66, a control-grid 5l and a cathode `'aS-8.

The plate 65 of the tube 64 is connected by means of a wire t@ to one terminal of the primary-winding l of the transformer 2li. The remaining terminal oi the said primary-winding i9 is connected by means of a wire 'lll to the highervalue plus terminal of the power-pack 53. The screen-grid et is connected by means of a wire li to a plus terminal of the power-pack, which plus terminal has a voltage materially less than the voltage of the plus terminal to which the wire 10 is connected. Interposed in the wire 'H is a resistor l2.

The control-grid El of the tube 64 is connected by means oi a wire 'i3 to the stationary contact i5 which is engaged by the contact I4 in a manner previously described in connection `with the description of Figs. l `and 2. Interposed in the wire i3 is a resistor lll, as sho-wn. The cathode 53 of the tube Bil is connected by means of a wire 'l5 to the negative terminal of the power-pack 63. Connected between the wires i3 and 'l5 is a resistcr 'id which is adapted to bias the control-grid 5? at the potential of the cathode 68 under conditions of no input signal, i. e., when the contact it is out of engagement with the contact l5.

The switch-arm l! is connected by means of a wire il to the negative terminal of a controlbattery It. The positive terminal `of the battery 'i3 is connected by means of a wire 'I9 to the wire l5 leading to the cathode 68 of the tube 64. Connected into the wire l@ is the wire 5| before referred to, which leads to an electromagnet such as 5S of Fig. l, and in which wire is interposed the switch E2 before referred to. The wire E0 referred to in the description of the apparatus of Figs. l and 2, is connected into the wire 'll and hence to the negative terminal of the controlbattery '53, as shown at the lower portion of Fig. 3. The wire Si is connected through the switch $2 to the wire l and also to the positive terminal of the control-battery '68.

The functioning of the apparatus of Fig. 3

When during turning movement of the control-cam lil, the contact le is brought into engagement with the contact l5, a potential will be thereby applied to the control-grid B1, which potential is negative with respect to the Voltage which at this time is being applied to the cathode 58. This action will result in the plate-current falling to Zero thus deenergizing the primary-winding i9 of the transformer 20 thus causing the energy stored in the core or the said transformer to act in the manner previously described in connection with the description of the apparatus of Figs. l and 2, to eiect the turning of the rotor.

As soon, in the revolution of the control-cam, as the contact lll is disengaged from the contact Ct* i l5, the respective potentials applied to the control-grid Si and cathode 68 lwill, by virtue of the resistor i6, achieve the same value, thereby permitting the iiow of plate-current and the energization of the primary-winding I9.

As the plate-current iows as above described, and the primary-winding -i is energized, the secondary-winding 22 will produce and induce voltage which as it rises will affect the synchronous electric motor in the manner previously described in connection with the apparatus of Figs. l and 2.

From the foregoing it will be seen that the apparatus illustrated in Fig. 3 acts basically in the same manner as that illustrated in the lower portion o Fig. l, to utilize both the build-up and decline of magnetic uX to effect the step-by-step rotation of a self-starting synchronous electric motor of the general type illustrated in Figs. l and 2.

The mechanically-operated switch mechanism including the parts li! to l5 inclusive above described, may obviously be replaced by any other suitable apparatus which will provide the impulses needed to cause the apparatus to function, such, for instance, as a photoelectric cell, microphone, capacity relay or the like.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim:

l. In an electric-impulse counter for counting direct-current electric-impulses of a wide range of frequencies, the combination with a splitphase self-starting synchronous electric motor of the type having a rotor provided with at least two toothed rotor-elements .permanently magnetized to opposite signs respectively, and a statorstructure including a first energizing-coil magnetically cooperating with one of the said toothed rotor-elements to effect the step-by-step rotation ol the rotor and a second energizing-coil magnetically cooperating with the other of the said toothed rotor-elements to effect the step-by-step rotation of the rotor; of a transformer having a primary and a secondary, the said secondary having a low-voltage tap and a high-voltage tap; means electrically connecting the said rst energizing-coil with the low-voltage tap of the said secondary; means electrically connecting the said second energizing-coil to the high-voltage tap of the said secondary; phase-splitting means associated with the said second energizing-coil to cause the magnetic ux developed thereby to assume an out-of -phase relationship with respect to the magnetic ux developed by the said first energizing coil; direct current interrupting means alternately energizing and deenergizing the primary or the said transformer with direct current to develop transients in the said secondary of alternately-opposite polarities; and indicating-means driven by the rotor of the said motor to count the cycles of alternate energizing and deenergizing of the said primary.

2. In an electric-impulse counter for counting direct-current electric-impulses of a wide range of frequencies, the combination with a split-phase self-starting synchronous electric motor of the type having a rotor provided with (ill two pairs of toothed rotor-elements permanently magnetized to opposite signs respectively, and a stator-structure including a rst energizing-coil magnetically cooperating with one of the said pairs of toothed rotor-elements to effect the stepby-step rotation of the rotor and a second energizing-coil magnetically cooperating with the other of the said pairs of toothed rotor-elements to effect the step-by-step rotation ci the rotor; of a transformer having a primary and a secondary, the said secondary having a low-voltage tap and a high-voltage tap; means electrically connecting the said rst energizing-coil with the low-voltage tap of the said secondary; means electrically connecting the said second energizing-coil to the high-voltage tap of the said secondary; phase-splitting means associated with the said second energizing-coil to cause the magnetic flux developed thereby to assume an outof-phase relationship with respect to the magnetic flux developed by the said iirst energizingcoil; direct-current interrupting means alternately energizing and deenergizing the primary of the said transformer with direct current to f: develop transients in the said secondary of alternately-opposite polarities; and indicating-means driven by the rotor of the said motor to count the cycles of alternate energizing and deenergizing of the said primary.

3. lin an electric-impulse counter for counting direct-current electric-impulses of a wide range oi frequencies, the combination with a splitphase self-starting synchronous electric motor of the type having a rotor provided with at least two toothed rotor-elements permanently magnetized to opposite signs respectively, and a stator-structure including a rst energizing-coil magnetically cooperating with one oi the two said toothed rotor-elements to eiiect the stepby-step rotation of the rotor and a second enel'- gizing-coil magnetically cooperating with the other of the two said toothed rotor-elements to effect the step-by-step rotation of the rotor; of a transformer having a primary and a secondary, the said secondary having a low-voltage tap and a high-voltage tap; means electrically connecting the low-voltage tap of the said secondary with the said first energizing-coil; means electrically connecting the high-voltage tap oi the said secondary with the said second energizing-coil; phase-splitting means interposed in the means electrically connecting the said high-voltage tap to the said second energizing-coil direct-current interrupting means alternately energizing and deenerg'izing the primary of the said transformer with direct-current to develop transients in the said secondary of alternately-opposite polarities; and indicatir neans driven by the rotor of the said motor d constructed and arranged to count the cycles of alternate energizing and deenergizing of the primary oi the said transformer.

ll. In an electric-impulse counter for counting direct-current electric-impulses of a wide range of frequencies, the combination with a splitphase self-starting synchronous electric motor of the type having a rotor` provided with two pairs of toothed rotor-elements permanently l"posit-e signs respectively, and a luding a first energizing-coil magnetically cooperating with one oi' the two said pairs ci toothed rotor-elements to effect the stepby-step rotationof the rotor and a second. energizing-coil magnetically cooperating with the other ol said pairs ci' toothed rotor-elements to effect the step-by-step rotation of the rotor; of

. transformer having a primary and a. secondary, the said secondary having a low-voltage tap and a high-voltage tap; means electrically connecting the low-voltage tap of the said secondary with the said first energizing-coil; means electrically connecting the high-voltage tap of the said secondary with the said second energizing-coil; phase-splitting means interposed in the means electrically connecting the said high-voltage tap to the said second energizing-coil; direct-current interrupting means alternately energizing and deenergizing the primary of the said transformer with direct-current to develop transients in the said secondary of alternately-opposite polarities and indicating-means driven by the rotor of the said motor and constructed and arranged to count the cycles of alternate energizing and deenergizing of the primary of the said transformer.

WEYMAN E. MAXWELL.

1 REFERENCES CITED UNITED STATES PATENTS Number Name Date '711,635 Lavens Oct. 21, 1902 1,468,490 Merrick Sept. 18, 1923 1,812,187 Ackerly f June 30, 1931 1,925,882 Smith Sept. 5,- 1(9313 2,122,307 Weich; June 23, 1933` 2,249,029 Mullenheim July 15, 1941 FOREIGN PATENTS Number Country Date 28,539 Great Britain 1902 

